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1 Name: Section: Number:

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4 Vocabulary Word Definition competition p.114 parasite p.117 host p.117 succession p.118 extinct p.120 endangered p.120 hazardous waste p.126 4

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8 Lesson 1: How are ecosystems balanced? page Interactions among living and nonliving things help maintain in ecosystems. 2. What do all plants and animals need to live and grow? 3. How does a forest meet the needs of a chipmunk? 4. How could a forest fire affect the balance of a forest ecosystem? 5. What keeps the balance in an ecosystem? 6. What happens when the number of organisms in a population increases? 7. If one of the populations in a community doubled, what would be likely to happen to that community? 8. What is something that might prevent a plant population from growing in size? 9. In what ways is balancing an ecosystem like balancing a seesaw? 8

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10 Lesson 2: How do organisms interact? page When species compete for a particular resource, what happens to the losers? 2. Populations grow when 3. What happens when two or more species must use the same limited resources? 4. How can wolves successfully hunt deer that are in a group? 5. What are two behaviors that help animals avoid or reduce competition? 6. When two organisms live closely together, the relationship can be 7. These special relationships exist between 8. Describe the relationship between algae and fungi. 9. In a relationship when one organism is helped and one is harmed, the helped is called, and the harmed is called. 10

11 10. Describe the relationship between the insect, balsam woolly adelgid, and Fraser fir tree. 11. What might happen to the parasite if its host were to die? Label the organisms are a host or a parasite in the relationship below: Tapeworms are flatworms that attach themselves to the intestines of animals such as cows, pigs, and humans. They get food by eating the host's partly digested food, depriving the host of nutrients. Fleas land on animals, such as dogs, and bite their skin, sucking their blood, and causing them to itch. The fleas, in turn, get food and a warm home. A tick is a small insect that lands on an animal, such as a deer, out in the woods. The tick feeds on the animal. The animal that it lands on may develop Lyme disease as a result. Head lice infest a creature s hair and suck blood from the scalp. This damages the creatures s scalp and leads to small blood loss and itching, while providing a habitat for the head lice. tapeworrm flea deer creature animal dog tick lice 11

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14 Lesson 3: How do environments change? page The process of gradual change from one community or organisms to another is called. 2. When does succession occur? 3. How does a warming climate affect an environment? 4. Using the illustration on page describe how a forest could have once been a lake. 5. If an animal is extinct. 6. Why might an animal become extinct? 7. When are species considered threatened? 14

15 8. When a species becomes extinct, what are some effects on the ecosystem to which in belonged? 9. What can we learn about the environment from studying fossils? 10. What are some events that change an environment very quickly? 11. What are two processes that change an environment slowly over a very long period of time? 12. How could a forest fire help to keep that forest ecosystem balanced? 13. If there is a flood, the population of which organisms might increase? Why? 13. What can a major flood do to an existing community? 15

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17 Lesson 4: How do people disturb the balance? page Why do humans have a great impact on the environment? 2. List some specific ways that humans change the ecosystem to get what they need. 3. What are some ways in which humans pollute the air? 4. What effects can pollutants have on other organisms? 5. List one way the water pollution affects the organisms that live there. 6. How do you think humans could return some balance to ecosystems? 6. What is a hazardous waste? 7. What effect could leaking hazardous waste containers have on the ecosystem? 8. If a company is planning to use land for mining, what plan must they have beforehand? 17

18 9. How has preservation of national parks helped the environment? 10. Name some natural environments in the United States that have been set aside for preservation as national parks. 18

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21 1. An organism that feeds on and harms a living thing is called a(n). 2. A species that is has no living members. 3. is the struggle between organisms to meet their needs. species. 4. A species that is at risk of dying out is a(n) 5. can be very harmful to organisms and the environment. 6.The process of one community gradually replacing another community is. 7. A(n) is an organism that provides energy or an environment for another organism. 21

22 1. Animals survive where their. 2. Grass makes and animals use it to help them breathe. 3. If a habitat is destroyed, animals may become. 4. Animals that eat other animals help keep the ecosystem. 5. A parasite hurts the, but helps itself. 6. One community gradually replacing another is called. 7. If the number of animals that get eaten decreases, the number of predators would. 8. In order to preserve nature s habitats, the US established. 1. Describe a balanced ecosystem. 2. List natural disasters that could change an ecosystem quickly. 22

23 3. Describe how a change in climate could affect that ecosystem. 4. If a fish fossil was found in the desert, what could you assume about that ecosystem? 5. If a meadow had too many rabbits, what would help balance that ecosystem? 6. How do people disturb the balance of the ecosystem? 23